Ribbon shift for error-obliterating typewriters



Oct. 27, 1964 w. H. WOLOWITZ RIBBON SHIFT FOR ERROR-OBLITERATING TYPEWRITERS William H. Wolowitz Filed March 16, 1962 ATTORNEY United States Patent 3,154,183 RIBBDN 51m"? FQR ERROR-OBLITERA'HNG TYPEWRITERS Willim H. Welowitz, 1742 Holly St., Washington, D.C. Filed Mar. 16, 1962, Ser. No. 180,229 3 Claims. (Cl. 19791) This invention pertains to typewriters, and aims to provide a typewriter having inter-related control means for selecting as between the imprinting and obliterating fields or portions of a composite ribbon.

In my copending patent application filed April 4, 1961, Serial No. 100,661, I have disclosed a typewriter ribbon having vertically-spaced fields respectively designed for (a) printing or marking in the usual manner of typewriter ribbons, and (b) obliterating erroneous markings by the application of a mark-obliterating or camouflage substance. Briefly, such a ribbon may have an upper (or lower) lengthwise printing or inked portion, and a lower (or upper) obliterating portion. In use, and with the ribbon installed on a conventional typewriter having a ribbon-vibrator of the field selecting type (for example, of the red/ black color selecting type), printing or typing proceeds as usual with the printing field of the ribbon in use.

Upon occurrence of an error, the typist back-spaces the carriage to bring the erroneously printed character (or one of such) again into printing position, and shifts the ribbon vibrator field control so as to bring the obliterating field of the ribbon into use upon the next operation of a character key. The key or keys corresponding to the erroneous imprints are again operated to superpose or over-print an obliterating substance from the ribbon onto the erroneous character imprint or imprints, following which the ribbon field-selecting control is returned to printing position, the carriage again backspaced, and the correct key or keys are struck to print the desired correct characters upon the blanked-out or obliterated spaces.

The present invention provides a modified typewriter especially adapted for use with a composite ribbon of the above type, and with which the necessary sequence of operations of the ribbon-field selecting control follows automatically as a result of the backspacing operations. In a typical form, the invention provides an auxiliary backspacing key for use in error-correcting operations, which key is linked mechanically to the ribbon-field selecting control in such a way that whenever the auxiliary key is operated so as to backspace the typewriter carriage to bring an erroneous imprint into position for obliteration, the ribbon field control is automatically shifted so that the obliterating field of the ribbon will be selected for presentation between the paper and the type faces. The other or usual backspacing key is likewise linked mechanically to the ribbon-field selecting control, so that after obliteration of an error, the operation of this backspacing key will restore the ribbon-field selecting control to its printing or marking condition.

The foregoing arrangement greatly facilitates the use of a composite ribbon of the type described, and makes the correction of typing errors fast and economical; all without undue complication or substantial additional cost.

Certain specific forms which the invention may take are described below, reference being made to the accompanying drawings, in which:

FIG. 1 is a schematic perspective view of the parts of a typewriter, otherwise of known and conventional kind, which relate to the invention.

FIG. 2 is a view similar to FIG. 1 showing an alternative construction of the invention.

In order to illustrate specific forms which the invention may take, and so that those skilled in the art may understand and make use of the novel principles thereof, I

3,154,183 Patented Oct. 27, 1964 have shown its application to particular makes of typewriters. In so doing, I do not mean to impose any unnecessary limitation, because the same principles are applicable to typewriters of other basic makes and types, as will be obvious.

Referring now to FIG. 1 of the drawings, I have illustrated in detail only those typewriter parts that are directly concerned with the invention, and for clarity have omitted (or shown only schematically) those which are purely conventional or are only remotely connected with the inventive features. Thus, I have indicated a main typewriter frame or body portion at 10, and the usual carriage 12, with platen roller 14, the carriage being designed for intermittent travel to the left as each printing key (or the space bar) is operated. A usual backspace key 16 is provided, each operation of which steps the carriage 12 one letter-space to the right. A ribbon vibrator 18 is also provided, and linked in the usual way to a common operator or bail which raises the ribbon 20, upon the operation of each character key, to present one or the other of its two fields to the printing position. A field-selecting control lever 22, itself of usual form and function, allows the typist to select as between an upper field 24 and a lower field 26.

For the purposes of explaining the present invention, I have shown a ribbon 20 whose upper field or longitudinal half 24 is inked in the conventional way so as to imprint characters on the paper 23, while its lower field 26 is provided with an imprint-obliterating substance as explained in my prior application mentioned above. To correct an erroneous imprint, the carriage is backspaced to bring the error into typing position, control 22 is operated to select the lower or obliterating ribbon field, and the erroneous character or keys again struck, to imprint the obliterating substance over the error or errors. The carriage is again backspaced, the control 22 shifted back to printing position, and the proper character keys operated to print the correct characters in the obliterated spaces.

To facilitate these operations, and to obviate the need for conscious recollection by the typist of the proper sequence, the invention provides (in addition to the conventional backspace key 16) an auxiliary backspace key 39. Linkages are provided so that as a preliminary to an error correction, the use of backspace key 30 automatically shifts field-selecting control 22 to its position selecting the obliterating field 26 of the ribbon, and leaves control 22 in this position. Additional backspacing may be performed as required (e.g., where the error or errors are several spaces to the left), but in any event control 22 is thus automatically brought to its obliterating position, and remains there until restored to printing position.

Moreover, and to avoid the need for a separate operation to restore control 22 to its imprinting position (in which field 24 of the ribbon will be restored to use), the normal backspace key 16 is also linked to control 22, in such a way as to restore the latter automatically to imprinting condition, preparatory to the operation of printing the correct character or characters in the obliterated (now blank) spaces. The usual function of backspace key 16 is fully maintained; for example, for underlining or the like. The usual function of control 22 is also retained; for example, where the typewriter is not provided with a ribbon of the composite typing/obliterating type. Control 22 may, of course, have the usual stenc' position in which the keys do not raise vibrator 18 at all.

Control 22 is pivoted on the machine frame at 31, and a detent spring 32 or the like keeps it in either of its selected positions. Only one character key 34 is shown, pivoted at 36 on the frame and linked to type bar 38 in the usual way. By Way of example, the key lever 40 has a tail portion 42, as do all the keys and the space bar, so that operation of any of these also operates the common bar or bail 44 linked to the carriage escapement, as well known in the art. As also well known, the common bail 44 additionally operates an intermediate link 46 which raises the ribbon vibrator 18 upon each key operation to bring one portion or field of the ribbon in position to be struck against paper 28 by the selected type face.

The selection as to which of the two fields of ribbon 20 is thus brought into play is shown schematically as controlled by lever 22 to which link 46 is pivoted for leftright motion to bring its tip beneath one or the other of the offset edges at the bottom of vibrator 18. If lower edge 48 is thus engaged, the vibrator will be lifted a maximum distance upon each key actuation, and the lower ribbon field 26 will be used, as shown in the dash-line position of lever 22. If lever 22 is in its full-line position, the tip of link 46 will lie beneath edge of the vibrator, and when link 46 is raised by key actuation, vibrator 18 will be raised a lesser distance, positioning the upper ribbon field 24 in position to be struck by the type face. A further position of lever 22, for stencil cutting, may be provided; link 46 being then fully withdrawn from beneath the vibrator.

In the arrangement shown, it is assumed that the upper portion or field 24 of ribbon 20 is the inking field and will be brought into use when lever 22 is in its full-line position. However, when the special Correction backspace key 30 is depressed, its lever arm 52 will depress the arm 54 of a pivoted rocking element 56, and tip 58 of this element will be raised, lifting a lateral extension 60 of control lever 22 and shifting the latter to its dashline position. This moves link 46 to the left, and any subsequent key operation will raise vibrator 18 its maximum distance, placing obliterating field 26 in position to be struck against the paper. Lever 22 will maintain this position even if several characters are thus obliterated following a plurality of correction-backspace operations of key 30.

After the desired obliterating operation or operations, the operator now has to backspace again to make the correct letter impression in the obliterated space. She uses the conventional backspace key 16 for this operation, and upon its first operation, its lever 62 will depress extension 60 and rock control lever 22 back to its solidline position. This of course moves link 46 to the right, and all subsequent character-key operations will lift vibrator 18 its lesser travel distance, causing ribbon field 24 to be brought into play to make the correct, and all desired subsequent imprints, in the normal manner.

Both of backspace keys 16 and 30 are connected to operate the carriage-stepping function in the left-to-right (backspace) direction, through the dog or pawl 64 acting on toothed bar 66. The dog 64 is shown in diagram fashion as linked to a crank lever 68 which is rocked forward by each actuation of either of keys 16 and 30. Toothed bar 66 is, of course, mounted on carriage 12 so as to cause the latter to step from left to right for each actuation of dog 64.

FIGURE 2 shows the application of the same selection principle to a typewriter of somewhat different design. Here the conventional backspace key 100 has a tail portion 102 slotted to receive and actuate a pull rod 104 when the key is depressed, and thus to pull the rod 104 and actuate backspace pawl 108 through crank 110 and rod 112. .This slotted (one-way) connection permits key 100 to backspace without also causing movement of the correction backspace key 114 which is similarly connected to the pull rod 104. Both keys thus can accomplish backspacing, but they are independently connected by links 116 and 118 to rockers 120 and 122 at points on opposite sides of their common pivot 123. These parts are shown partly exploded for clarity.

A link 124 is connected to rocker 120, and at its right end has a slotted portion 126 engaging a pin 128 on the 4 control lever 130 which selects the ribbon field in a known way, through the position of its shaft 132. The slot connection here allows lever 130 to stay where it has been moved by link 124, and also enables the operator to control the ribbon field selection manually by a knob 134 on the front panel; for example, as amongst the redblack-stencil choices of a conventional typewriter. The length and position of the slot in 126 are chosen so that movement of link 124 to the left of its rest position (to which it is always restored by the spring of the key-lever when key 160 is released) shifts lever 130 to select (for example) the inked ribbon field, or to leave it there if it was already so positioned. This is the position shown in the drawing. Conversely, movement of link 134 to the right (upon depression of key 114) shifts lever 130 to cause selection of the obliterating ribbon field. Link 134 controls lever 130 through its slotted portion 136. V A stencil position of lever 130 may lie between these two positions if desired. The mechanism controlled by lever 130 is, as conventional, arranged to maintain its selected position until lever 130 is purposefully moved to a new position.

The operation will be readily understood by assuming first that lever 130 is in its printing position, as shown, with pin 128 at its left-hand extremity. Typing proceeds as usual, and normal backspacing by key pulls link 124 leftwards, but this has no effect on lever since the pin 128 is already at the left end of the slot in 126. If a correction is to be made, key 114 is used for backspacing, and link 134 moves to the right, shifting lever 130 so as to bring the obliterating ribbon field into use, and leaving 130 in that position, even if several characters are to be corrected. After the desired obliteration, further operations of key 100, to again backspace in preparation for printing one or more correct characters, shifts pin 128 to the left again, because the pin would then lie at the right extremity of the slotted portion of 126. When so shifted, the ribbon field will again be selected for typing the correct characters.

In referring to a backspace key as one which steps the conventional paper carriage in a direction opposite to the writing direction, I mean to refer to the direction of carriage motion during the typing process; e.g., though the direction or progression of characters along a typed line is ordinarily from the left to right, the carriage motion itself is from right to left. Hence, the backspace motion is from left to right, or opposite to the writing direction of the carriage as it moves during the normal typing process.

Having disclosed my invention in detail, so that those skilled in the art can understand and practice it, I wish it to be understood that the details thus given are intended as exegetic and not restrictive, the scope of my invention being defined in the following claims.

What is claimed is:

1. A typewriter for use with ribbons providing. a print ing field and a print-obliterating field, said typewriter including character-printing mechanism, a paper support mechanism, and spacing means for stepwise moving said mechanisms relative to one another in a forward direction to accomplish printing of a line of characters, a ribbon vibrator actuated by the printing control keys to bring a ribbon field momentarily into operative position upon actuation of each of said printing control keys, a ribbon field-selecting lever operable between two detented positions for controlling the extent of motion of the vibrator to select the particular ribbon field that is thus brought into operative position, and key-controlled backspace drive means for stepwise moving said mechanisms relative to one another in the backward direction in letter-width increments upon successive operationsof said backspace drive means; a pair of backspace keys both connected to operate said backspace drive means, and respective lostmotion connections between said respective backspace 3 keys and said field-selecting lever to shift the latter between detented positions respectively corresponding to that backspace key which was last operated.

2. A typewriter in accordance with claim 1, in which said lost-motion connections include a common rocker element arranged for rocking movement by said backspace keys.

3. A typewriter in accordance with claim 1, in which said lost-motion connections include a rocker element in cooperative relation to said ribbon-field selecting lever, and in which said respective backspace keys are secured to respective backspace key levers having portions adjacent the ends of said rocker element for shifting said rocker element in respectively opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS 1,171,961 Kidder et a1 Feb. 15, 1916 1,273,302 Wright July 23, 1918 1,277,500 Stickney Sept. 3, 1918 1,905,118 Nadell Apr. 25, 1933 FOREIGN PATENTS 528,589 Great Britain Nov. 1, 1940 

1. A TYPEWRITER FOR USE WITH RIBBONS PROVIDING A PRINTING FIELD AND A PRINT-OBLITERATING FIELD, SAID TYPEWRITER INCLUDING CHARACTER-PRINTING MECHANISM, A PAPER SUPPORT MECHANISM, AND SPACING MEANS FOR STEPWISE MOVING SAID MECHANISMS RELATIVE TO ONE ANOTHER IN A FORWARD DIRECTION TO ACCOMPLISH PRINTING OF A LINE OF CHARACTERS, A RIBBON VIBRATOR ACTUATED BY THE PRINTING CONTROL KEYS TO BRING A RIBBON FIELD MOMENTARILY INTO OPERATIVE POSITION UPON ACTUATION OF EACH OF SAID PRINTING CONTROL KEYS, A RIBBON FIELD-SELECTING LEVER OPERABLE BETWEEN TWO DETENTED POSITIONS FOR CONTROLLING THE EXTENT OF MOTION OF THE VIBRATOR TO SELECT THE PARTICULAR RIBBON FIELD THAT IS THUS BROUGHT INTO OPERATIVE POSITION, AND KEY-CONTROLLED BACKSPACE DRIVE MEANS FOR STEPWISE MOVING SAID MECHANISMS RELATIVE TO ONE ANOTHER IN THE BACKWARD DIRECTION IN LETTER-WIDTH IN- 